Evolution: Objections to an Internal Mechanism

I didn’t compare myself to him.

People who laugh at other people often can’t differentiate between a Galileo and a Bozo.

A lot of mainstream scientists haven’t an original thought in their heads.

I still only want to know what objections are there to the possible existence of an internal mechanism. I don’t even want to argue about it, just a list is all.

Jorolat

…the dopey buddy of Joseph Stalin, who insisted that he could grow corn in Siberia? I ask this because , many years ago, a western biologist went through some of Lysenko’s research, and found some very slight evidence that evolutionary change could be triggered by environment. I though that lamarkism had been totally disproved…anybody know any more about this?

A lot of people, myself included, saw this as a comparison between yourself and Galileo. Just for the record.

As for the OP, it might be helpful if you could give examples of specific “internal mechanisms”, as no one seems to know what they are in the abstract.

I think I get it. I wish you could stop me if I’m wrong, jorolat, but here goes, anyway:

By “internal mechanism,” you mean some process which changes an individual’s genes (or just the genes within the germ cels), yes? This would imply that some part of evolution is self-directed, or an “if this environment continues, my progeny won’t survive well, so lemme tinker with the genes in my own sperm before I go mate next time” kind of thing (either brain-directed or not).

Is this actually testable? Technically, yes, I suppose. If it’s something which is supposed to work at the lowest levels of life, then one could simply grow a ton of bacteria, and measure the mutation rate while subjecting them to all sorts of stressors. If they mutate more often than would be expected by chance, that’d support the idea that something more than simple evolution was taking place.

The test becomes more complicated for sexual reproduction, since researchers would be forced to figure out which genes came from which parent, etc. But this isn’t impossible, just very difficult.

So, it is testable, but I can only assume that the first test has been done, probably several times already (with negative results), and the second (sexual reproduction) is probably such a big pain in the butt that nobody wants to try it.

On the other hand, if the “internal mechanism” hypothesis is being applied to actual random mutations (in other words, someone is claiming that they’re not random, but directed by preceeding generations), then there’s no way to test that, since the mutations look random. Perhaps this is what Gould compared to mysticism?

Oh, by the way, don’t assume that that John Latter quote works in reverse. And don’t forget that Einstein obviously saw lots of curious people - otherwise the quote might read “it is a miracle that curiosity ever survives formal education.”

I’m wavering between abandoning the kaleidoscope analogy or expanding upon it. I wanted a way to convey the difference between patterns (changes in allele frequencies) that have no seperate physical existence of their own and the natural realities (individual organisms) that produce such patterns.

The geocentric theory is an historical example of how an intellectual explanation can largely fit the facts and yet still remain completely at variance with the reality it attempts to describe. I feel there are “some” elements of evolutionary theory that are much the same.

Below is a quote from the “Spandrels” paper:

6. ANOTHER, AND UNFAIRLY MALIGNED, APPROACH TO EVOLUTION

*In continental Europe, evolutionists have never been much attracted to the Anglo-American penchant for atomizing organisms into parts and trying to explain each as a direct adaptation. Their general alternative exists in both a strong and a weak form. In the strong form, as advocated by such major theorists as Schindewolf (1950), Remane (1971), and Grassé(1977), natural selection under the adaptationist programme can explain superficial modifications of the Bauplan that fit structure to environment: why moles are blind, giraffes have long necks, and ducks webbed feet, for example. But the important steps of evolution, the construction of the Bauplan itself and the transition between Baupläne, must involve some other unknown, and perhaps “internal,” mechanism. We believe that English biologists have been right in rejecting this strong form as close to an appeal to mysticism.

But the argument has a weaker – and paradoxically powerful – form that has not been appreciated, but deserves to be. It also acknowledges conventional selection for superficial modifications of the Bauplan. It also denies that the adaptationist programme (atomization plus optimizing selection on parts) can do much to explain Baupläne and the transitions between them. But it does not therefore resort to a fundamentally unknown process. It holds instead that the basic body plans of organisms are so integrated and so replete with constraints upon adaptation (categories 2 and 5 of our typology) that conventional styles of selective arguments can explain little of interest about them. It does not deny that change, when it occurs, may be mediated by natural selection, but it holds that constraints restrict possible paths and modes of change so strongly that the constraints themselves become much the most interesting aspect of evolution.*

I feel part of what G and L are saying is that it is important to take the actual reality of a subject under discussion into account (in this instance the fact that organisms are integrated) before theorizing about it. Yet alone coming to conclusions !

Re the Weismann Barrier: An internal mechanism would require a signalling pathway from the integrated organism to its equally integrated germ cells. Steroid hormones enter the nucleus of germ cells - which is not to say they are part of an internal mechanism but it does establish the fact that “communication” occurs.

Jorolat

[QUOTE]
*Originally posted by jorolat *
**

Aha! Here’s the heart of the confusion, I believe.

The environment or the creature affected by said environment does NOT “tell” germ cells how to form (so that the organisms they spawn will be well-adapted). Rather, germ cells–both within an individual and throughout a species–naturally vary by certain degrees. Offspring formed from those germ cells that thrive and pass on their own germ cells in the greatest number are said to be–after the fact, mind you–better adapted.

I originally felt somewhat at a loss at people saying they didn’t understand the original post but perhaps it would have been clearer if I had said “an internal evolutionary mechanism”.

I’m specifically interested in a possible homeostatic mechanism which is described at the URL below. The page is a couple of years old but it should convey the concept, I’m in the middle of a rewrite and intend to include “objections” as part of it.

Natural Selection is an explanation a la geocentric theory and you can’t test it. I am suggesting that there is a mechanism rather than a process.

Jorolat

How do you propose testing this mechanism?

Have you found any evidence that a living body’s cells can communicate such complex information to germ cells?

oops - forgot the URL!

I have to go now and will reply to any outstanding posts tomorrow

Jorolat

G&L wrote:

Oh. OH! Okay. G&L are saying here that S, R & G are claiming that natural selection is fine for the “little things,” but for initiating or transitioning between forms, it’s not enough, and there must be “something else” (some strange “internal mechanism” that no biologist has yet found, or maybe God perhaps?) directing the process.

What that “something else” is is not now known. Testing it, therefore, is next to impossible. Once that “something else” is figured out, then one could make a hypothesis about how forms ‘should’ change, and apply it to either the data available in the fossil record, or just wait a few million years and see if modern-day Baupläne change as predicted. Can’t test the hypothesis until it exists, though - and right now it doesn’t.

If I’m interpreting the “weak” form correctly, it basically just says that when large transitions occur, something really interesting goes on - more interesting than, say, populations of short-necked animals slowly evolving into giraffes. I agree. But in this form, there’s no need to add in the “something else” hypothesis, and hence no scent of mysticism.

jorolat wrote:

Ooops - forgot it again, didn’t you?

Jorolat:

“Natural Selection is an explanation a la geocentric theory and you can’t test it. I am suggesting that there is a mechanism rather than a process.” -Jorolat

Not occording to the OED online, which says:

“natural selection: the operation of natural causes by which those individuals of a species that are best adapted to the environment tend to be preserved and to transmit their characters, while those less adapted die out, so that in the course of generations the degree of adaptation to the environment tends progressively to increase.”

Note the phrase “operation of natural causes”, which, unless I am mistaken, can be replaced with “process of natural causes” without significantly changing the meaning.
Nor according to Stephen Jay Gould, who, in “Ever Since Darwin” states:

1- “Natural Selection is defined by Spencer’s phrase “survival of the fittest””

2- “The principle of natural selection depends upon the validity fo an analogy with artificial selection. We must be able, like the pigeon fancier, to identify the fittest beforehand, not only by their subsequent survival. But nature is not an animal breeder; no preordained purpose regulates the history of life. In nature, any traits possessed by survivors must be counted as “more evolved”; in artificial selection, “superior” traits are defined before breeding even begins. Later evolutionists…recognised the failure of Darwin’s analogy and redefined “fitness” as mere survival. But they did not realize they had undermined the logical structure of Darwin’s central postulate. Nature provides no independent criterion of fitness; thus, natural selection is tautological.”

3- “My defense of Darwin is neither startling, novel, nor profound. I merely assert that Darwin was justified in analogizing natural selection with animal breeding. In artificial selection, a breeder’s desire represents a “change of environment” for a population. In this new environment, certain traits are superior a priori; (they survive and spread by our breeder’s choice, but this is a <result> of their fitness, not a definition of it). In nature, Darwinian evolution is also a response to changing environments. Now, the key point: certain morphological, physiological, and behavioral traits should be superior a priori as designs for living in new environments. These traits confer fitness by an engineer’s criterion of a good design, not by the empirical fact of their survival and spread.”

4- “Thus, it is not true…that any traits possessed by survivors must be designated as fitter. “Survival of the fittest” is not a tautology. It is also not the only imaginable or reasonable reading of the evolutionary record. It is testable. It had rivals that failed under the weight of contrary evidence and changing attitudes about the nature of life. It has rivals that may succeed, at least in limiting its scope”

Thus, we can see that ‘natural selection’ is not an “explaination a la geocentric theory” of evolution, but rather the process by which Darwinian evolution is actually carried out. Perhaps my choice of the word “method” was poor, but I thought it was clear.
Furthermore, we can see at least one reason why the kaleidascope analogy fails: it describes only the numeric proportions of the alleles in question (i.e. whether or not they survived and spread) without explaining the reason behind the failure or sucess of each allele.

DaveW:

I think the “weak” form says something more like ‘once the entire body plan is put together no really large changes can occur, and the process by which the body plan forms is guided by natural selection’. This would seem to be consistent with many of the ideas Gould expressed in “Wonderful life: The Burgess Shale and the Nature of History”.

Is it that eyelessness in a lightless environment is a positive asset, in terms of not devoting energy to useless eyes? Or is it simply that random mutation will eventually erase any structure if selective pressure against deformities is removed?

Firx wrote:

I’ve gotta start reading Gould’s books, instead of just works which reference his books. :slight_smile:

Given your interpretation, it sounds like mine was sort of “backwards,” but I guess that’s what’ll happen when one only has a few paragraphs and none of the background material to work with. But either way, the “weak” version seems reasonable.

But now I’m guessing that the answer to the OP depends largely on one’s definition of “body plan.” When you get down to the nitty-gritty, while there are massive obvious ‘superficial’ differences among, say, land vertebrates, the “head, trunk, four limbs, and a tail” body plan pretty much applies to all of them (even if some limbs or tails have withered away to nothing). Give or take a pair of limbs or two, one might even include the bony fishes.

So, I guess the question is, at what phylogenic level does a “body plan” reside? Certainly not ‘kingdom’, but perhaps ‘phylum’? ‘Class’? I mean, if it’s close to the top of the tree, then it seems like the main objection to the “internal mechanism” idea is really just that when multicellular life came to be (perhaps several different times), the ‘choice’ of body plans was truly wide-open. And because of that, any explanation other than “random chance and natural selection” really is just an attempt at complicating the picture or is, indeed, an “appeal to mysticism.”

To extend my example above, if “having a spine” is pretty much one of the ‘baupläne’, then one is forced to go way back in time to find any evidence that this unknown “internal mechanism” was ever in use. A question which springs instantly to mind is: “what is the most recent ‘body plan’ to have come into existence?” Is it so vastly different from everything else around at the time that the “random chance and natural selection” hypothesis is somehow lacking in its ability to explain it?

(Why does it seem to me that invoking this “internal mechanism” is just another flavor of the “intelligent design” concept of “irreducible complexity?” It feels like it’s saying “evolution can’t possibly explain such massive structural differences, so there must be something else.” An argument from ignorance coupled with a probable misunderstanding of evolution?)

(Why does it seem to me that invoking this “internal mechanism” is just another flavor of the “intelligent design” concept of “irreducible complexity?” It feels like it’s saying “evolution can’t possibly explain such massive structural differences, so there must be something else.” An argument from ignorance coupled with a probable misunderstanding of evolution?) **
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I think you’re right; it does seem like the “evolution can’t (or at least natural selection can’t) explain this, so there must be something more” argument. As for the body plans, although I am not sure I think that things that fall into many categories, like arms or spinal columns, are regarded as part of the integrated organism only after they have undergone further changes. For example, many organisms have feet, but how many have feet that were once hands like humans do?

Jorolat:

“I am suggesting that there is a mechanism rather than a process.” -Jorolat

I forgot to ask, but what distinction are you making between “process” and “mechanism” here?

Yes, in a lightless environment, eyelessness is a positive attribute.

Okay, Firx, that’s a hypothetical ‘body plan’ many steps away from the root fo the tree. And the G&L quote from jorolat has them talking about basic body plans, from which I gather that turning a hand into a foot is pretty much a superficial change. Whereas turning a hand into, say, a second working head would be much more drastic, and definitely a change in body plan.

As far as “integrated organisms” go, it seems that G&L are speaking of such as a way of thinking about an organism (as opposed to ‘atomization’), and not as any definite point in a species’ evolution. I mean, there’s no way a foot will survive without being ‘integrated’ into the rest of an organism, no matter how closely it functions as a hand, so I’m not sure that your use of “integrated” is the same as G&L’s.

At first glance the geocentric theory would appear quite different from the earlier belief that the world was flat. They do share one characteristic though - they are both egocentric.

It’s a question of whether one wants an intellectually satisfying explanation of a reality or whether one wants to discover the true nature of that reality - hence the reference to how well the geocentric theory explained the known facts and yet was completely wrong. Outside of the human intellect there are only individual organisms, lotsa 'em, and so I do feel there is something else: an internal evolutionary mechanism.

My aim here, however, remains the same - to find out what objections there may be to an internal mechanism that I’m not aware of.

Reading your post again, and in case I haven’t made it clear, I don’t feel the mutations that occur in the germ cells are entirely random but I would stress that neither do I feel they are directed.

Jorolat

Sorry I wasn’t able to answer yesterday. I hope the replies I’ve given have made it clearer, if not the URL in my signature should do so.

Jorolat

In 1640 Galileo wrote a letter to Fortunio Liceti in which he said:

“If Aristotle were to see the new discoveries recently [made] in the heavens, whose immobility he had asserted, because no alteration had previously been seen in them, he would now without doubt state the contrary.”

This statement highlights the danger of placing dependence on words frozen in time without taking into account how those words would change if their author had had access to the discoveries that have since been made.
   Lamarck, for example, published his “Zoological Philosophy” in 1809 and is today popularly associated with “the inheritance of acquired characteristics” whereby organisms somehow direct their own evolution. On the basis of Galileo’s words, however, it could be argued that had Lamarck been alive in the 1890’s, over thirty years after publication of “On the Origin of Species”, his views would have progressed from the moment in time in which they had been caught. With access to the discoveries and discussions that occured throughout the 19th Century it is conceivable that Lamarck might even have reached broad agreement over J. Mark Baldwin’s proposal of an indirect factor in evolution, known today as the “Baldwin Effect”, that appeared in the 1896 paper “A New Factor in Evolution”.
   Naturally this suggestion is open to argument but if sufficient to illustrate Galileo’s implied principle, that words frozen in time should be differentiated from those cast in stone, then the inappropriateness of interpreting natural phenomena in purely Lamarckian terms is readily apparent.

An indirect internal evolutionary mechanism would not be Lamarckian.

Jorolat